In the radiation performance test of the wireless terminal, radiation signals in a plurality of directions and receiving sensitivities in the plurality of directions should be measured, and then total radiation power and total radiation sensitivity are obtained by mathematical calculation. Since the antenna of the wireless terminal is not directional usually, but radiates to all directions of space, when testing the wireless performance of the wireless terminal, a basis idea is to put a device under test to a center of a sphere, and to measure signal strengths at a plurality of positions on surface of the sphere by the test antenna, and to calculate the total radiation strength after obtaining measurement values of all positions.
At present, according to a test standard of CTIA (Cellular Telecommunications Industry Association), a big circle method is used mainly. A mobile terminal to be tested is put on a center of a three dimensional turntable, and may rotate around two axes with the turntable. By using one test antenna and setting both the mobile terminal and the test antenna in an anechoic chamber, the direct signals emitted to the test antenna by the mobile terminal are received by the test antenna, and the radiation signals emitted to other directions by the mobile terminal are absorbed by an absorbing material set in the anechoic chamber. When testing, the mobile terminal is rotated with a preset angle interval according to test demand. The mobile terminal is stopped to measure signal strength when rotated to each position. Test time may be reduced by adjusting the angle interval. Test result is generated by integration and other data processing after measuring radiation signals in each direction.
However, as testing speed of this system is low, and it needs that the distance between the test antenna and the device under test should be larger than a far field distance, the device under test is irradiated with the plane wave of the test antenna, thus that a huge volume, a high manufacturing cost, and a small application scope of the testing system are caused.